Production of mixtures of nitrogen and hydrogen from bituminous fuels



21, 1933- I c. SCHNEIDER ET AL 98,96

PRODUCTION OF MIXTURES OF NITROGEN AND HYDROGEN FROM BITUMINOUS FUELS Filed April 9, 1931 NVENTOR 5 Chris? z'an ScZnez'oZer I .HIez'nriJz Buelefisch BY Umr ATTORNEYS ?atcnted Feb. 2t, 1933 umrro stares were? ABATE-NT orrica CHRISTIAN SCHNEIDER AND HEINRICH BUETEFISGH, F NEUBOESSEN, em,

ASSIGNOBS TO I. G. FABIBENINDUBTBIE AK'I'IENGEBELLSGEAI'T, 0F FBAHKI'OBT- ON-E'HE-IA EF, GEBEAM monomer: or magmas or nrrnoenn AND macaw rnounrrumous nouns Applicatioaflledjprfl 9, 1931, Serial'fio. 528,828, and in Germany May 1, 1930.

The present invention relates to the roe v duction of mixtures of nitrogen and by ro- 5 bituminous fuels such as brown coal, lignite,

peat, oil shale and the like to low temperature carbonization by passing therethrough hot gases obtained from a gasifying process. For this purpose'producers having low temperature carbonization attachments are frequently employed or better still shaft i111 naces which are subdivided into difierent treatment zones by several grates, so that the single processes are carried out separate from each other on the single grates.

It has also been proposed to split up the hydrocarbons contained in industrial or natural gases into carbon monoxide and hydro en by incomplete combustion.

We ave now found that mixtures of nitrogen and hydrogen are obtained in an advantageous manner from bituminous fuels by subjecting the fuels to low temperature carbonization by ineans oi scavenging gases, which are obtained by gasifying the low temperature carboniz ation residues arranged in several layers one above the other with the aid of steam or air, which may also be enriched in oxygen, or both employed in such an amount that the layer of'fuel is brought into vigorous motion on its bed and by converting the gas mixture obtained from the low temperature carbonization, after separating the condensable components, preferably by cooling down to from to G. into a mixture of nitrogen and hydrogen by incompletely burning the hydrocarbons contained therein preferably with air,

which may also be enriched in oxygen, converting the resulting carbon monoxide with steam and separating the carbon dioxide.

. If the gases obtained by the said gasificatioli of the low temperature carbonization residues contain already suficient nitrogen, the subsequent incomplete combustion may also be efi'ect/ed with oxygen.

The compositionof the gasifying agent, which may consist for example of a mixture of air enriched with oxygen and steam, as

well as the composition of the gas containing oxygen necessary for the partial combustion of the hydrocarbon contained in the gas formed, as which oxygen may be employed fr'or example, de nd according to the present invention simp y on the desired composition of the final gas as regards nitrogen and hydrogen and can be determined by previous calculations or by appropriate experiments.

The conversion of carbon monom'de into carbon dioxide by means of steam is carried out at temperatures ranging from 380 to 620 6., preferably between 400? and 500 G. and preferably in the presence of catalysts.

The advantages of the process according to the present invention consist not only in a considerable simplification of the apparatus; but also in the great saving of energy which results from this combination.

As special advantages of the process may, be mentioned:

1. A. mixture of nitrogen and hydrogen having a high; content of hydrogen is obtained having any desired composition as neither a preheating of the gasifying agent,

nor an external supply of heat to the process is necessary.

2. The combination of the production of mixtures of nitrogen and hydrogen with the simultaneous low temperature carbonization of fuels renders possible a far reaching utilization for the low temperature carboniza tion of the sensible heat of steam which has remained undecomposed in the watergas reaction. As a result of the presence of steam during the low temperature carbonization, an increased yield of tar of excellent quality is obtained. The bitumen contained in the fuel is completely obtained as tar and the hydrogen in the. final gas is formed simply by the watergas reaction of the small coke and by the decomposition of the hydrocarbons.

3. Apart from ashes and carbon dioxide,

only hi h ualit final products are obtained from t e el, irstly a mixture of nitrogen and h drogen capable of being further worke up, for example into ammonia, and secondly a high quality tar, the entire energy content of the low temperature carbonization residues being completely utilized in the process.

The nature of this invention will be further described with reference to the accompanying drawing which illustrates diagrammatically an arrangement of apparatus suitable for carrying out the invention but the invention is not restricted to this arrangement.

A shaft furnace A, which is subdivided into different treatment zones by several grates R R R R and R is supplied with fuel, as for example predried brown coal, from a bunker F through a conveyor G. A gasifying agent consisting of air enriched with oxygen and steam is introduced into the shaft furnace A below the lowest grate B, through a pipe E employed in such an amount that each layer of fuel is brought into vigorous motion on its bed. The small coke formed from the brown coal is thus completely gasified. The gasifying temperature at the grate R amounts to about 900 C. and the distance between the grates R and R is adjusted so that the gasifying gas laden with undecomposed steam passes through the grate R at a temperature of about 800 C. This gas mixture then effects the low temperature carbonization and the driving out of the residual water content of the coal on the grates R R R and R The gas mixture laden with the products of the low temperature carbonization is freed from any dust which it has carried along with it in a dust removing plant, either a cyclone device or electrical means, arranged in the upper part S of the shaft furnace A and leaves the shaft furnace A at H at a temperature of about 250 C. The mixture of gases, water vapor and tar vapors then pass through a condensing plant B in which the anhydrous tar, benzines and low temperature carbonization water are removed from the gases by the methods usually employed in the low temperature carbonization industry. The gases leaving the condensing plant B which have been cooled to about 20 C. still contain a certain percentage of gaseous hydrocarbons. In order to remove these hydrocarbons the gas mixture is converted with a mixture of oxygen and nitrogen introduced at P into a combustion chamber D after it has been brought to a high temperature in a heat exchanger C. The gas mixture enters the heat exchanger C at J, flows therethrough in counter current to the hot gases coming from the combustion chamber D and leaves at K at a temperature of about 750 C. It then passes into the comessee? bustion chamber at L. The gas mixture is strongly heated by the heat of reaction set free uring the combustion and leaves the combustion chamber D at M at about 1100 C. It then enters the heat exchanger 0 at N and leaves it a ain at O cooled to 250 C. The mixed gas t us obtained is then freed from carbon monoxide in the usual manner by conversion with steam and the carbon dioxide thus formed is removed in the usual manner. The mixture of nitro en and hydrogen which remains may be irectly emloyed for the synthesis of ammonia without urther treatment.

The following example will further illustrate the nature of this invention, but the invention is not restricted to this example.

Ewample Mid continent brown coal is worked up in the said apparatus after having been dried to about 8 to 10 per cent. The brown coal, which has been dried in the usual manner in a steam or fire-gas dr ing plant, has an average water content 0 yields 14.9 per cent of tar.

428 cubic meters of air enriched with oxygen and having an oxygen content of 43.8 per cent and 622 kilo rams of steam are employed for the gasi cation of each metric ton of predried brown coal.

The yield of high quality anhydrous low temperature carbonization tar amounts to 142 kilograms per metric ton of predried brown coal.

After separating the tar, benzines and low temperature carbonization water there remain 1380 cubic meters of ,a gas mixture having the composition 20.2 per cent of carbon dioxide, 22.1 per cent of carbon monoxide, 36.0 per cent of hydrogen, 17.9 per cent of nitrogen, 1.0 per cent of h drogen sulphide and 2.8 per cent of hy rocarbons.

58.3 cubic meters of a mixture of oxygen and nitrogen containin 79.2 per cent of oxygen are necessary for the incomplete combustion of the hydrocarbons. 1418 cubic meters of a gas are then obtained having the composition 19.7 per cent of carbon dioxide, 25.5 per cent of carbon monoxide 35.0 per cent of hydrogen, 18.7 per cent of nitrogen, 1.0 per cent of hydrogen sulphide and 0.1 per cent of methahe. This gas mixture is freed from carbon monoxide by conversion with steam. After removing the carbon dioxide thus formed, about 1134 cubic meters of a mixture of nitrogen and hydrogen containing about per cent of h drogen is obtained which may be directly employed for the synthesis of ammonia.

What we claim is 1. A process for the production of a mixture of hydrogen and nitrogen from bituminous fuel which comprises subjecting said fuel while arranged in layers to a low tem- 8.4 per cent and I dues from said carbonization, also arranged in la ers, to a gasification by blowing 'upward y through said layers of residue, at asifying agent in an amount suficient to bring said layers of residue into vigorous motion on their beds, the low temperature carbonization of said fuel being efiected b leading the gases arising from said cation still hot through the layers of fue to be carbonized, separating by condensation the condensable compounds contained in the gases and vapors issuing from the low temperature carbonization, subjecting the non-condensed gases to incomplete combustion, carbon monoxide thereby being formed, treating the incompletely burned gases with steam at a peratm between 380 and 620 (3., the carbon monoxide thus being converted into. carbon dioxide, removing said carbon dioxide from the gases and eitfecting at least one of the steps of gasification and incomplete combustion by means or a as containing nitrogen.

2. t process for the production of a mix-' ture of hydrogen and nitrogen from bituminous fuel which comprises subjecting said fuel while arrangcdin layers to a low temperature carbonization, subjecting the residues from said carbonisation, also arranged in layers, to a gasification by means of steam and air by blowing upwardly through said layers of residue, a gasityin agent in an amount suficient to bring sai layers of residue into vigorous motion on their beds, the

low temperature carbonization of said fuel being edected by leading the gases arising from said gasification still but through the layers of fuel to be carbonized, separating by condensation the condensable compounds contained in the gases and vapors issuing from the low temperature carbonization, subjecting the non-condensed gases to incomplete combustion with air, carbon monoxide thereby being formed, treating the incompletely burned gases with steam at a temperature between 380 and 620 C the carbon monoxide thus being converted into carbon dioxide, and removing said carbon dioxide from the gases.

3. A process for the production of a mixture of hydrogen and nitrogen from bituminous fuel which comprisessubjecting said fuel while arranged in layers to a low temperature carbonization, subjecting the residues from said carbonization, also arranged in layers, to a gasification by blowing upwardly through said layers of residue, at gasifying agent in an amount suficient to bring said layers of residue into vigorous motion on their beds, the low temperature carbonization of said fuel being effected .by

- leading the gases arising from said gas'ification still hot through the layers of fuel to be carbonized, separating by condensation the condensable compounds contained in the gases and va ors issuing from the low temperature car nization, subjecting the noncondensed gases to incomplete combustion, carbon monoxide thereb being formed, treating the incompletely burned gases with steam at a temperature between 380 and 6209 (3., the carbon monoxide thus being converted into carbon dioxide, and removing said carbon dioxide from the gases, effect ing at least one of the steps of gasification and incomplete combustion by means of a gas containing nitrogen, the amounts and compositions of the gases containing nitroen used for said gasification and for said incomplete combustion being so adjusted that the said gases freed from carbon dioxide represent a mixture which'may directly be employed as initial material for the synthesis of ammonia.

d. A rocess tor the production of a mixture of hydrogen and nitrogen from bituminous fuel which comprises subjecting said fuel while arranged in layers to a low temperature carbonization, subjecting the residue from said carbonization, also arranged in layers, to a gasification with steam and air enriched in oxygen by blowing upwardly through said layers of residue, a gasitying agent in an amount sufiicient to bring said layers of residue into vigorous motion on their beds, the low temperature carbonizetion of said fuel being efiected by leading1 the gases arising from said gasification sti hot through the layers of fuel to be carbonized, separating b condensation the condensable compoun 5 contained in the gases and vapors issuing from the low temperature carbonization, subjecting the noncondensed gases to incomplete combustion with air enriched in oxygen, carbon monoxide thereby being formed, treating the incompletely burned gases with steam at a temperature between 380 and 620 (1, the carbon monoxide thus being converted into carbon dioxide, and removing said carbon dioxide from the gases.

5. A process for the production of a mixture of hydrogen and nitrogen from bituruinous fuel which comprises subjecting said fuel while arranged in layers to a low temperature carbonization, subjecting the residue, from said carbonization, also arranged in layers, to a gasification by means of steam and air enriched in oxygen by blowing upwardly through said layers of residue, a gasifying agent in an amount sufiicient to bring said layers of residue into vigorous motion on their beds, the low temperature carbonization of said fuel being effected by leading the gases arising from said gasification still hot through the layers of fuel to be carbonized, separating by condensation the condensable compounds contained in the gases and vapors issuing from the low temperature carbonization by coolinz said gases and vapors down to from 2025 (3., subjecting the non-condensed gases to incomplete combustion with air enriched in oxygen, carbon monoxide thereby being formed, treating the incomoletely burned gases with steam at a temperature between 400 and 500 C., the carbon monoxide thus being converted into carbon dioxide, and removing said carbon dioxide from the gases. In testimony whereof we have hereunto set our hands. 7

CHRISTIAN SCHNEIDER.

HEINRICH BUETEFISCH. 

